Ethernet Support Guide for HP-UX 11i v3

Example 7 Displaying current receive flow control settings
To display the current receive flow control setting, use the following command, where ppa identifies
the device by its PPA number. Sample output is shown.
nwmg -g -A rx_fctrl -c lanppa
lan0 current values: Receive Flow Control = On
Example 8 Displaying current transmit flow control settings
To display the current transmit flow control setting, use the following command, where ppa identifies
the device by its PPA number. Sample output is shown.
nwmgr -g -A tx_fctrl -c lanppa
lan0 current values: Transmit Flow Control = On
3.6.3 Setting the flow control parameter
The following examples show how to set receive and transmit flow control.
NOTE: Certain versions of the 10GigEthr-02 (iexgbe) product and supported hardware impose
limitations on flow control and the use of Jumbo Frames. For details about flow control and Jumbo
Frame support for your version of 10GigEthr-02, refer to the release notes for that version.
Example 9 Setting receive flow control
HP recommends setting receive flow control permanently to persist across reboots. To turn receive
flow control on or off permanently, edit the driver's configuration file to set the parameter value to
ON or OFF. For the name of the receive flow control parameter supported by your device, refer to
Table 10 (page 28). For example, to set receive flow control for all ports on the iexgbe device
to ON, specify the following:
HP_IEXGBE_RX_FLOW_CONTROL=ON
Alternatively, use the nwmgr command to set receive flow control immediately and permanently,
specifying the --sa option in the following format where ppa identifies the device PPA number:
nwmgr --sa -A rx_fctrl= {on|off} -c lanppa
Example 10 Setting transmit flow control
HP recommends setting transmit flow control permanently to persist across reboots. To do so, edit
the driver's configuration file to set the parameter value to ON or OFF. For the name of the transmit
flow control parameter supported by your driver, refer to Table 10 (page 28).
Alternatively, use the nwmgr command to set receive flow control immediately and permanently,
specifying the --sa option in the following format, where ppa identifies the device PPA number:
nwmgr --sa -A tx_fctrl= {on|off} -c lanppa
3.7 Displaying and setting maximum transmission unit (MTU) parameter
and Jumbo Frames
Jumbo Frames are large, 9000-byte data frames that can provide more efficient and
higher-performance transmission. You enable Jumbo Frames by setting the maximum transmission
unit (MTU) size to 9000 bytes. Jumbo Frames are supported only when the link speed is configured
to 1000 Mbit/s or greater. For Gigabit and 10 Gigabit Ethernet, the acceptable MTU settings
depend on which driver and which HP-UX release you are using. For a summary of the allowable
MTU sizes for each Ethernet driver and release, see Table 11 (page 30).
3.7 Displaying and setting maximum transmission unit (MTU) parameter and Jumbo Frames 29